// Copyright [2020] <unknown>
#include <bits/stdc++.h>
using namespace std;
// #define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
#define dbg(x...) { cerr << "\033[32;1m" << #x << " -> "; err(x); }
void err() { cerr << "\033[39;0m" << endl; }
template<typename T, typename... A>
void err(T a, A... x) { cerr << a << ' '; err(x...); }
#else
#define dbg(...)
#endif

#define sz(x) ((int)x.size())

typedef long long LL;


const int N = 1e5+50;
int n, a[N], k;
int main(int argc, char const *argv[]) {
    // code
    int x;
    cin >> x;
    int ans = x / 500 * 1000 + (x % 500 / 5 * 5);
    cout << ans << endl;
    return 0;
}
